In the group that I'm playing in, one of the PC's has a high loyalty Simstar contact that, according to their backstory they've had a bit of a fling with and, as a result, she got hardcore fired from Horizion for it.

So, the GM and I, are trying to figure out what we could do to draw this contact into game play more.

What would you use a Simstar contact for?
What would they want from the PC's?

My personal perception of a Simstar would be a highly valued asset with very limited personal freedom (I.E. William Gibsons' character "Angie Mitchell" from Count Zero and Mona Lisa Overdrive. IIRC, it has been some time since I read the novels).

Thoughts?

Well, for what a 'Runner would want is information and knowledge on the rich people. Rumours, layouts of the house, who they're jamming, and so on.

And what would they want from the PCs? Protection, elimination of the competition, extraction from their own contract, intimidating the Newsies into not running that fluff piece, a bit of fun on the town...

Okay, but seriously. Have you seen Ocean's Twelve? Imagine how well the egg scene would have gone if they'd had an actual movie start working for them instead of someone pretending to be the star.

Movie(Sim) stars have an amazing ability to go places that mere mortals wouldn't generally be allowed. They can also be wonderful for creating distractions. Think how busy a corp's security would be if a big star walked into their place with a gaggle of admirers, paparazzi, etc.

The sim star could want their main competition for some upcoming role to be delayed to an audition. They could want protection. They could want help with discreet movements. Perhaps they need help because someone is blackmailing them. Heck, maybe they want to try some rare meat that is hard (illegal) to get.

By Simstar, I imagine you mean a highly charismatic/beautiful socialite character. If so, here's what I would do with him/her:
-distraction: Nothing beats having a Simstar befriending your mark, so you can approach them unnoticed
-information gathering: wealthy, popular people have access to some privileg info, particularly about the upper class.
-social proof: Afraid your team's uncouth Sammie won't make it past the guards to the dinner party? Dress him up appropriately, and hook him up with the Simstar, and there's almost no party you can't enter.
-Job offers: anything from bodyguard jobs to getting rid of stalkers will do.

A simsense star should make a great fixer for the less common requirements (i.e. other than guns and biowarfare agents). Successful celebrities tend to attract people who want to make money out of them, offering unusual (often illicit) services with discretion. A simstar would likely know people who could get them whatever they fancied – drugs, body-sculpting, security measures, VIP tickets, party invites, high-end fashion, joygirls/boys, SOTA gear not yet publicly available, false IDs, credit, etc.

If the star is ex-corp then it may be their supply chain is no longer available, but they'll have hobnobbed with a lot of influential people who still know who to ask for what.